The present invention relates to bicycle brakes comprising bicycle cables and handlebar levers. In particular, this present invention relates to a new bicycle brake assembly which includes a torsion spring and slide guide with slide member. The current bicycle brake assembly exhibits: self-alignment, uniform forces upon both brake shoes, simplicity of construction and simultaneous engagement of brake shoes.
Many existing bicycles lack effective anti-lock capability. For example, the rider initially depresses prior art brake levers suddenly with maximum effort. The maximum braking force for the rotating wheels occurs just prior to zero rotation, and then the wheels stop rotating and skid.
Furthermore, most brake systems do not self-align, thereby causing one brake shoe with increased applied force from the bicycle cable, to drag against the bicycle rim. This drag results in increased friction and additional work to move the bicycle forward. The lack of self-alignment also causes an uneven bicycle stop as the user depresses the brake levers. My modified bicycle brake possesses a self-align feature, because the bicycle cable and associated components are mechanically constrained within a single rigid mechanical housing known as a slide guide. The torsion spring which connects the bicycle cable movement to the brake arms is vertically aligned along the center of this rigid housing. Consequently brake arms always receive the same torque from the bicycle cable, because there is no unequal upward force from the torsion spring and rigidly constrained bicycle cable whenever the user compresses the handlebar brake levers. In addition, because the brake shoes more evenly contact bicycle rims, the user experiences greater brake pad longevity.
U.S. Pat. No. 4,163,482 (Lauzier) discloses a center pull caliper brake for bicycles. The center-pull brake cable connects to the two calipers by a spring. The spring also serves as a retractor and has the shape of an inverted V. The spring's center connects to the brake cable by a cable anchor, while the spring ends wind around corresponding pins. The two springs ends each press against a corresponding abutment upon each respective caliper.
U.S. Pat. No. 6,308,806 B1 (Nielsen) discloses a brake cable with one end connected to a brake actuator and an opposite end anchored to the handlebar stem. The cable passes through a motion transfer mechanism comprising a link member and a yoke with a pair of arms. The arms are mutually spaced with apertures which contain a shaft with a pulley. The bottom end of the link member contains a shaft with two pairs of rollers. From the brake actuator the cable passes into a steerer tube and around the pulley, re-enters the steerer tube and then exits the cable guide assembly. When a brake handlebar lever is operated, the cable exerts an upward force upon the link member.
U.S. Pat. No. 5,894,913 (Sugimoto) discloses a brake device with a torsion spring, or return spring and a casing. The casing and spring are both coaxially mounted upon a pivot pin, and there are spacing sleeves between the front plate and rear plate comprising a brake arm. The spring is mounted within the casing so that its first end engages a part of the brake fixing mechanism and a second end engages an adjustment screw. The brake cable asymmetrically enters this brake device at the upper brake arm position.
U.S. Pat. No. 4,290,506 (Nagano et al.) discloses a center-pull brake assembly with a brake member which contains a vertical slot. The vertical slot allows vertical adjustment.
U.S. Pat. No. 5,505,105 (Kuo) discloses a connector which is designed to maintain a constant angle between a third cable, which attaches to a bicycle lever, and the connector itself. A first and second cable attached within the connector also connect to a corresponding brake arm. U.S. Pat. No. 5,560,260 (Kuo) discloses another connector, which contain first and second brake cables, and which attaches to corresponding brake arms. A third brake cable extends to a handlebar lever and traverses a bolt within the connector. The bolt is engaged to a nut by a spring and washer. The spring and washer position the third brake cable, and the third brake cable is adjustable by unscrewing the bolt.
According to U.S. Pat. No. 5,560,260 (Kuo), the angle between the first brake cable and the third bracket cable is equal to that between the second brake cable and the third brake cable. Consequently, when the third brake cable is pulled upward, it exerts an equal force to each first and second brake cable. If an adjustment is necessary to alter the distance between the first and second brake cables, the operator loosens the bolt and pulls the third brake cable vertically for a new connector position.
U.S. Pat. No. 5,582,272 (Chen) discloses a center-pull first bicycle cable with a bolt engaged through the upper portions of a bridging device. An aperture in the middle of the bridging device engages a second brake cable. A channel is formed within a bridging device so the two brake cables can align with each other and the center portion of the bridging device.
U.S. Pat. No. 5,484,032 (Li) discloses a hanger device which connects a pull cable and yoke cable within a bicycle brake assembly. The device includes a vertical guide rod fastened to the bicycle fork. A slidable member is mounted upon the guide rod and connects to the pull cable. The slidable member has a transverse-receiving groove which receives the middle section of the yoke cable. There is also an insert member and a fastening unit.
Still referring to Li, the slidable member has four walls, and three of these walls comprise vertical keyways. The slidable member contains the guide rod. Keys extend into corresponding keyways of the guide rod, so that the slidable member slides vertically upon the guide rod.
Still referring to Li, the pull cable extends into the guide rod while its exposed end portions extend into the insert member through an aperture within the slidable member. The yoke cable has two portions, each of which connect to a respective brake arm, as well as an intermediate portion which traverses the grooves of the slidable member. When a brake lever connected to the pull cable is actuated, the pull cable moves upwards, thereby causing upward movement of the slidable member. The yoke cable moves upward, and thereby causes pivoting movement of the brake arms towards each other.
U.S. Pat. No. 4,869,351 (Romano) discloses a center-pull flexible cable which interacts with an articulated parallelogram with four pairs of connecting rods. The cable passes through a block-like second element with first and second vertically aligned apertures. The cable is held in place by a grub screw which is tightly inserted within the lower positioned aperture of this second element. The lowermost aperture has an axis perpendicular to the aperture axis, and the threaded inserted grub screw presses against the cable.
U.S. Pat. No. 4,256,205 (Hamar) discloses a center-pull bicycle cable connection apparatus with a screw rigidly connected to the main actuation cable. The main cable screw engages an adjustment member in a rotating manner, and the screw therefore changes the main cable's tension. U.S. Pat. No. 4,163,482 (Lauzier) discloses a center-pull bicycle cable attachment to a spring which connects to two overlapping calipers.
None of the above patents include a structure for a sliding bicycle brake cable connection in which the entire bicycle cable is mechanically retrained along a centerline through the slide guide mechanical casing of the brake assembly. Similarly, none of the above patents include a torsion spring which is mounted upon a slide bolt along that same centerline, so that the force applied to each brake arm is always equal to the other. The pivoting caliper or cantilever arms are also attached along this centrally aligned axis. In sum, the current invention incorporates a vertical structure for mechanical restraint of the bicycle cable, structurally unique sliding components, cooperating torsion spring and attachment of pivoting brake arms along this same centerline.